It is preferred, if not required for safety, that the space between adjacent passenger cars of a train or like vehicle be enclosed to permit the safe and convenient movement of passengers between the cars. Such an enclosure must not only protect the passengers from the weather and other environmental factors, but it also must be capable of absorbing the forces engendered by the moving train particularly, for example, when the train is navigating a curve at a relatively high speed.
The most successful device known to date which addresses these needs is a system such as shown in U.S. Pat. No. 4,599,947. There each adjacent railroad car is provided with reinforced molded rubber material which surrounds the door of the car in an arch-like fashion. On one end the rubber is attached to a plate mounted on the railway car and at the other end is attached to face plates. The face plates of adjacent cars carry wear plates which abut each other when the cars are coupled. Step plates are provided over which passengers may walk when passing through the diaphragm enclosure from one car to another.
However, although it is the best train diaphragm known at the present time, the device of U.S. Pat. No. 4,599,947 is not without its problems. In particular, when trains equipped with such diaphragms negotiate sharp turns, the face plate of the diaphragm often binds with the rubber and the mounting plate and can be latched or locked thereto which can damage the flexible diaphragm material and destroy the integrity of the passageway between cars. Such is particularly prevalent in railway cars of the type that have a short coupling expanse between cars.
Another problem unaddressed by the prior art is that the floor or sill of the passageway formed by the diaphragms is not completely enclosed. Thus, air, dirt and noise from underneath the diaphragm can enter the passageway from around the step plates. Attempts to seal the sill area have included placing a urethane coated sponge material in the open areas. However, such material is not only expensive, but it is also quite susceptible to permanent deformation or coating cracks with resulting sponge deterioration permitting the air to pass therethrough, or requiring frequent replacement.
In addition, in the prior art diaphragms, moisture can seep in between the wear plates of adjacent diaphragm assemblies and run into the passageway. Such is not only irritating to the passengers but also, because the water will pick up the black phenol resin from which the wear plates are normally constructed, the black drippings can stain the clothing of the passenger.
Thus, the prior art has not addressed several problems encountered in the safe and convenient passage between railroad cars--which problems are solved by the diaphragm assembly according to the present invention.